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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 16 
sealed. During 1921 and 1922 a photographic method was employed 
whereby photographs were taken weekly of every frame containing 
sealed brood, and counts made later from the negatives, the sealed brood 
only being counted because of its greater clearness. As a result of the 
continuance of this work for three years, there are now available counts 
of brood made at weekly intervals during an entire active season for 
fifty-three colonies. The curves which form the basis of this paper 
are from one of these colonies for two consecutive seasons. 
It is a matter of common apiary experience that the brood increases 
rather rapidly in the spring up to a maximum and then falls off during the 
remainder of the year. The rapidity with which the maximum is 
reached is especially striking in regions of early honey-flows with no 
later honey-flows of consequence. Furthermore, it is generally recog¬ 
nized that brood-rearing naturally reaches its maximum at or just after 
the height of the honey-flow. This is attested by the existence of such 
apiary practices as dequeening during a honey-flow, removing brood, 
and the like. Nevertheless, a clear definite understanding has not yet 
been reached of all of the factors causing increased brood-rearing ac¬ 
tivity or its decline. Nor has it been established whether the brood¬ 
rearing curve is regular and uniform in its rise to the maximum and in its 
subsequent decline, or whether breaks and irregularities may not occur 
both in the rise and decline. It is of interest then to glance at the season¬ 
al brood curve of some individual colony. 
The colony whose brood-rearing activity during 1921 and 1922 is 
described in this paper was located at the Bee Culture Laboratory at 
Somerset, Md. It was wintered unpacked in two, 10-frame Langstroth 
hive-bodies. During the course of the two years nothing whatever was 
done to stimulate brood-rearing. The queen, however, was allowed to 
roam at will through the hive. Although there was no restriction to 
any possible expansion of the brood area, on no occasion was brood found 
•outside of the first three hive-bodies. The queen used throughout both 
seasons had been introduced into the colony in late summer in 1920 as 
soon as she had commenced to lay. In brief, each spring found this 
colony with a fairly strong force of bees, a prolific queen, combs com¬ 
posed chiefly of worker cells, and no shortage of stores. 
To determine its seasonal brood-rearing activity, counts of all of the 
sealed brood in this colony throughout both seasons were made once 
•each week. From these counts brood curves for each season have been 
constructed, these curves being so similar that they will be discussed as 
one. They show quite clearly that in the vicinity of Washington the 
